Acta neurochirurgica. Supplement
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Acta Neurochir. Suppl. · Jan 1999
Theory and practice of microdialysis--prospect for future clinical use.
The application of microdialysis for neurochemical monitoring in neurosurgery and neurointensive care is rapidly expanding in a number of clinical centers around the world. In order for microdialysis to become a future routine method in these clinical settings a number of problems, outlined in this communication, must be solved by the clinical researchers and the commercial companies. Regardless of the future success as a routine method, it is already obvious that microdialysis will be an important clinical research tool for years to come, providing new important insights into the pathophysiology of acute human brain injury.
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Acta Neurochir. Suppl. · Jan 1999
ReviewThe role of transcranial Doppler in the management of patients with subarachnoid haemorrhage--a review.
Introduced 15 years ago, transcranial Doppler (TCD) recordings of blood-velocity in patients with recent subarachnoid haemorrhage (SAH) have two objectives: to detect elevated blood velocities suggesting cerebral vasospasm (VSP) and to identify patients at risk for delayed cerebral ischemic deficits (DID). The pathophysiological cascade causing DID is complex. Discrepancies between blood velocities and DID (presuming that there actually is an "ischemic threshold" for blood velocity in absolute terms, which seems most unlikely) have been demonstrated, particularly in patients with elevated intracranial pressure (ICP) levels. ⋯ This probably explains why the clinical value of TCD is still debated. There is still uncertainty as to the best method to prevent and to treat VSP, and the overall outcome after SAH depends on so many factors besides VSP. Conclusive evidence may therefore be hard to obtain, and it appears sound to conclude that even with advanced investigation technology available, proper selection, pre- peri- and postoperative care and timing of surgery remain cornerstones in the management of these patients,--equal in importance to their treatment in the operating room or in the interventional angiography suite.
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Acta Neurochir. Suppl. · Jan 1998
Comparative StudyAn avoidable methodological failure in intracranial pressure monitoring using fiberoptic or solid state devices.
Failure of intraventricular pressure (IVP) measurement in case of catheter blockage is believed to be eliminated by using intraventricular microtransducers. We report about an avoidable methodological error, which may affect the reliability of IVP measurement with these devices. Intraventricular fiberoptic or solid state devices were implanted in 43 patients considered to be at risk for catheter occlusion. ⋯ In patients treated with Type B devices, no erroneous pressure recording could be identified, irrespective if CSF drainage was performed or not. Transducers, which are simply placed inside the ventriculostomy catheter require fluid coupling. They may fail, either during CSF drainage or when the catheter is blocked or placed within the parenchyma.
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Severe head injury with and without peripheral trauma is the most frequent cause of death and of severe disability up to 45 years. Outcome is determined by two major factors, the extent and nature of the irreversible primary brain damage, and the evolving secondary sequelae, which contrary to the former are responsive in principle to therapeutic intervention. An improvement of outcome from severe head injury can be expected only from an increased efficiency of the measures to prevent secondary brain damage. ⋯ Current results and experiences with establishment of this comprehensive research organization are presented, where no less than 31 hospitals. Institutions and organizations, and a study group of more than 40 physicians, students and statisticians are collaborating. Emerging data appear to be suitable to further improve pertinent aspects of the patient management as a basis to lower the incidence of secondary brain damage from severe head injury.
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Acta Neurochir. Suppl. · Jan 1998
Effects of mild and moderate hypothermia on cerebral metabolism and glutamate in an experimental head injury.
In this study we sought to determine the optimal brain temperature for treating compression-induced cerebral ischemia. Six cats each were treated with a deep-brain temperature of 37 degrees C (control), 33 degrees C (mild hypothermia), or 29 degrees C (moderate hypothermia). Intracranial pressure (ICP) and cerebral blood flow (CBF) were monitored, as were arteriovenous oxygen difference (AVDO2) and cerebral venous oxygen saturation (ScvO2). ⋯ Reactive hyperemia after balloon deflation was decreased after both mild and moderate hypothermia, as was the tissue volume showing Evans blue dye extravasation. Extracellular glutamate increased in control animals, an effect most effectively suppressed in the mild hypothermia group. These data favor 33 degrees C as the optimal temperature for treating compression-related cerebral ischemia.